This application relates to a method and apparatus for the microwave depolymerization of hydrocarbon feedstocks, including plastic materials. An earlier effort is embodied in U.S. Pat. No. 6,184,427 entitled “Process and Reactor for Microwave Depolymerization of Plastic Materials”, which is assigned to the assignee of the present invention. This patent discloses, among other things, using the interaction of microwave and sensitizers in order to provide heating and depolymerization of hydrocarbons. The present invention is an improvement upon such U.S. patent.